Hagel was speaking to reporters in Abu Dhabi. He says the White House has informed members of Congress that, within the last day, U.S. intelligence concluded with “some degree of varying confidence” that Syrian President Bashar Assad’s regime has used chemical weapons — specifically sarin gas.

Hagel says, quote, “It violates every convention of warfare.”

President Barack Obama has said the use of chemical weapons would be a “game-changer” in the U.S. position on intervening in the two-year-old Syrian civil war.